The present invention generally relates to an additive composition effective for increasing total dietary fiber in a wide variety of food products.
For the preparation of refined foods, cereal grain is usually subjected to a milling process. In these processes, the hulls (bran) and germ, which are the structures rich in minerals and vitamins, are more or less completely removed. Refined mill products, such as masa flour, consist chiefly of the endosperm. Portions of the corn kernel removed from the endosperm, such as the hulls or bran, are considered to be waste by-products which are often put into animal feed.
Botanically, a maize kernel is known as a carypoisis, a dry, one-seeded, nutlike berry in which the fruit coat and seed are fused to form a single grain. Mature kernels are composed of four major parts: pericarp (hull or bran), germ (embryo), endosperm and tip cap. The average composition of whole maize, and its fractions, on a moisture-free (dry) basis is as follows:
Pericarp: The maize kernel is covered by a water-impermeable cuticle. The pericarp (hull or bran) is the mature ovary wall which is beneath the cuticle, and comprises all the outer cell layers down to the seed coat. It is high in non-starch-polysaccharides, such as cellulose and pentosans. {A pentosan is a complex carbohydrate present in many plant tissues, particularly brans, characterized by hydrolysis to give five-carbon-atom monosaccharides [pentoses]. It is any member of a group of pentose polysaccharides having the formula (C5H8O4)n found in various foods and plant juices.} Because of its high fiber content, the pericarp is tough.
Germ: The scutulum and the embryonic axis are the two major parts of the germ. The scutulum makes up 90% of the germ, and stores nutrients mobilized during germination. During this transformation, the embryonic axis grows into a seedling. The germ is characterized by its high fatty oil content. It is also rich in crude proteins, sugars, and ash constituents. The scutulum contains oil-rich parenchyma cells which have pitted cell walls. Of the sugars present in the germ, about 67% is glucose.
Endosperm: The endosperm contains the starch, and is lower in protein content than the germ and the bran. It is also low in crude fat and ash constituents.
Tip cap: The tip cap, where the kernel is joined to the cob, is a continuation of the pericarp, and is usually present during shelling. It contains a loose and spongy parenchyma.
In milling corn to obtain flour, the corn is first cleaned, and is then usually passed through a scourer to remove the tip from the germ end of the kernel. The corn is then tempered by the addition of water to a moisture content which is generally from about 21% to about 24%. The corn is frequently then passed through a corn degerminator, which frees the bran and germ, and breaks the endosperm into two or more pieces. The stock from the degerminator is generally dried to about 14% to 16% moisture in revolving dryers equipped with steam coils, and is then cooled in revolving or gravity-type coolers. The stock is next passed through a hominy separator, which first separates the fine particles, and then grades and polishes the larger fragments into four sizes. The various grades of broken corn are passed through centrifugal-type aspirators to remove any loose bran from the endosperm fragments, and produce milled cereal by-products such as aspirated bran. These by-products are waste products which heretofore had little value.
xe2x80x9cAspirated branxe2x80x9d from corn and other cereal grains, is an impure form of whole bran which generally contains some of the floury endosperm, and the starch and protein present therein, and some germ, and the protein present therein, and may contain some grits. Generally, most of the germ and grits will already have been removed from the cereal grain at this point in the milling process. It is possible for the aspirated bran to contain no germ, to contain all of the germ, or to contain any amount of germ in between. Similarly, the aspirated bran fraction may contain no grits from the cereal grain, may contain all of the grits, or may contain any amount of the grits in between.
Masa flour (dry corn flour which has usually been nixtamalized) and masa (corn dough which has usually been nixtamalized) are raw materials which may be used for the preparation of tortillas, corn chips, tortilla chips, taco shells, nachos and similar products.
Nixtamalization is the cooking of cereal grain, such as whole corn kernels, in a medium which usually contains an alkaline agent, such as water containing lime (CaO). Thereafter there is steeping (soaking) of the cereal grain for a period of time, for example, for about three to about fourteen hours, subsequent draining of any remaining cooking liquor, washing of the cereal grains, and grinding of the cereal grains to make with drying a cereal grain flour, which may be added with water to make a cereal grain dough from which tortillas and related products may be prepared.
It would also be advantageous to provide an additive which increases the fiber content and nutritional value of products produced from the flour or dough as well as other food products by providing an additive with a higher fiber content, and with additional vitamins and minerals. Further, it would be advantageous to produce such an additive composition without the production of liquid waste with a material which is essentially a waste by-product from the milling of cereal, such as whole corn. It would also be advantageous to provide tortillas and related products prepared with such an additive which would retain the flavors and other positive attributes of tortillas and related products prepared without such additive.
The additive of the present invention imparts the advantageous properties described above to tortillas and other food products, such as juices, other beverages and yogurt. Moreover, food products produced witch the additive composition will be more nutritious and healthful than products which do not contain the additive. Products with the additive of the invention will have a higher fiber content, and also include vitamins and minerals which are present in the by-product from which the additive is made.
The present invention provides a high, fiber additive composition which is a by-product of milling processes wherein the high fiber additive enhances the fiber content of a variety of products including flour, yogurts, beverages, baking items, snack foods such as pretzels, cereal products such as breakfast cereals, and salsa. The additive is provided from a high fiber, low starch source of plant material. In a very important aspect of the invention, the source of high fiber, low starch is cereal bran or a mixture of bran obtained from the commercial dry milling of corn, wheat, barley, oats, rice, rye, sorghum or any other cereal grain. In an alternative aspect of the invention, the high fiber, low starch source may be soy hulls. The low levels of starch in the additive composition makes it less sticky than additives with higher levels of starch, and hence, the additive composition of the invention can be used in a wide variety of food products.
In an important aspect, the high fiber additive composition comprises aspirated cereal bran having less than about 15 weight percent starch, which starch content is gelatinized, at least about 2 weight percent protein, and at least about 75 weight percent total dietary fiber. In an important aspect, the starch in the cereal bran has been substantially gelatinized. In another important aspect, the starch in the cereal bran is gelatinized by cooking it with at least about 0.05 weight percent, based upon the weight of the bran, calcium oxide or lime or equivalent thereof. This should provide the additive with at least about 0.025 weight percent calcium, based upon the weight of the additive. The additive should also provide a pH of at least about 7 when it is mixed with water and the additive comprises about 10 weight percent of the additive/water mixture. In another important aspect, the high fiber additive composition comprises soy hulls having a very low starch content and at least about 2 weight percent protein, and at least about 75 weight percent total dietary fiber.
In an important aspect, the additive composition comprises soy hulls having little or no starch. The soy hulls also comprise at least about 2 weight percent protein and at least 75 weight percent dietary fiber. In this aspect of the invention which utilizes soy hulls, there is little if any starch to be gelatinized. The soy hulls, however, are heat treated under the same conditions used to gelatinize the starch in cereal bran. This heat treatment opens the structure of non starch polysaccarides such as arakinoxylans, beta glucans and pectic substances.
The invention also includes a process for making the additive composition. The method comprises mixing aspirated cereal bran comprising less than about 15 weight percent starch or soy hulls with water or an alkaline agent and water to provide an aqueous fiber mixture and cooking the aqueous fiber mixture (or alkaline aqueous mixture) to gelatinize the starch in the cereal bran or open the polysaccharide structure in the soy hulls and provide a cooked bran or soy hulls. The cooked product is dried. If an alkaline agent is used during cooking, the cooked product is dried without first removing aqueous alkaline water, such as lime water, to provide a dried alkaline-treated bran. Thereafter, the water treated or alkaline treated bran is milled to a particle size, such that it will pass through a screen mesh with openings of not greater than 0.1 square mm. In an important aspect, the high fiber additive is pulverized such that at least 70 weight percent of the material is smaller than 500 microns. In an important aspect, the bran is corn bran, the starch is corn starch, and the bran additive composition comprises aspirated bran having less than about 15 weight percent starch, of which at least about a substantial amount has been gelatinized. In this aspect, the alkaline agent, such as lime, comprises from about 0.05 to about 5 weight percent based upon the weight of the by-product or bran. The amount of lime, water and cooking are effective for gelatinizing the starch.